﻿AQUATIC 
  INSECTS 
  IN 
  THE 
  ADIRONDACKS 
  54I 
  

  

  cc 
  Wings 
  with 
  many 
  veins 
  and 
  not 
  covered 
  with 
  whitish 
  powder 
  

  

  d 
  Wing 
  veins 
  all 
  terminating 
  at 
  the 
  distal 
  border 
  of 
  the 
  wing 
  in 
  a 
  suc- 
  

   cession 
  of 
  symmetric 
  forks, 
  the 
  ultimate 
  forks 
  often 
  forming 
  a 
  

   peripheral 
  zone 
  around 
  the 
  distal 
  margin 
  of 
  the 
  wing 
  

   e 
  Cross 
  veins 
  between 
  the 
  radius 
  and 
  its 
  sector 
  numerous 
  (ten 
  or 
  more) 
  

   (Green 
  or 
  yellowish 
  insects 
  : 
  lace 
  wing 
  flies 
  ; 
  larvae, 
  aphis 
  lions, 
  

   arboreal 
  ; 
  pupating 
  in 
  cocoon 
  of 
  silk, 
  attached 
  to 
  the 
  plants 
  on 
  

  

  which 
  they 
  have 
  lived) 
  Chrysopidae 
  

  

  ee 
  Cross 
  veins 
  between 
  the 
  radius 
  and 
  its 
  sector 
  few 
  (two 
  to 
  six) 
  

  

  Hemerobiidae 
  

  

  dd 
  Wing 
  veins 
  meeting 
  the 
  outer 
  wing 
  margin 
  in 
  straight 
  lines. 
  Forks 
  

  

  fewer, 
  more 
  remote 
  from 
  the 
  margin 
  and 
  less 
  symmetric 
  .. 
  Sialidae 
  

  

  The 
  two 
  families 
  which 
  contain 
  our 
  aquatic 
  species 
  will 
  now 
  be 
  con- 
  

   sidered 
  in 
  detail. 
  Their 
  larvae 
  have 
  already 
  been 
  distinguished 
  in 
  the 
  

   key 
  to 
  the 
  orders 
  of 
  aquatic 
  insect 
  larvae. 
  

  

  Family 
  sialidae 
  

   Alder 
  flies 
  ^ 
  fish 
  flies 
  ^ 
  dobsofis, 
  etc. 
  

  

  This 
  family 
  comprises 
  but 
  few 
  genera 
  and 
  species 
  ; 
  but 
  the 
  large 
  size 
  

   and 
  the 
  enormous 
  number 
  of 
  individuals 
  of 
  some 
  of 
  the 
  species 
  make 
  

   them 
  a 
  well 
  known 
  part 
  of 
  the 
  aquatic 
  population. 
  Few 
  insects 
  of 
  incon- 
  

   spicuous 
  coloration 
  and 
  secretive 
  habits 
  are 
  so 
  well 
  known. 
  Every 
  

   species, 
  in 
  larval 
  as 
  well 
  as 
  adult 
  stages, 
  is 
  attractive 
  food 
  for 
  fishes, 
  and 
  

   many 
  of 
  them 
  are 
  among 
  the 
  insects 
  most 
  highly 
  prized 
  and 
  most 
  com- 
  

   monly 
  used 
  for 
  bait. 
  

  

  The 
  adult 
  insects 
  do 
  not 
  wander 
  far 
  from 
  the 
  borders 
  of 
  their 
  native 
  

   streams 
  or 
  ponds; 
  they 
  are 
  generally 
  found 
  sitting 
  closely 
  on 
  some 
  

   support, 
  with 
  wings 
  folded 
  like 
  a 
  roof 
  over 
  the 
  back. 
  They 
  fly 
  but 
  little. 
  

  

  The 
  larvae 
  are 
  somewhat 
  cylindric, 
  with 
  large 
  heads 
  and 
  very 
  large 
  

   raptorial 
  mandibles, 
  and 
  have 
  on 
  the 
  sides 
  of 
  each 
  of 
  the 
  first 
  seven 
  or 
  

   eight 
  abdominal 
  segments 
  a 
  pair 
  of 
  long, 
  conspicuous 
  lateral 
  filaments. 
  

  

  The 
  eggs 
  are 
  deposited 
  on 
  any 
  convenient 
  support 
  near 
  the 
  water, 
  in 
  

   clusters 
  whose 
  form 
  varies 
  with 
  the 
  genus, 
  and 
  to 
  a 
  less 
  extent, 
  with 
  the 
  

   species. 
  

  

  Our 
  three 
  genera 
  may 
  be 
  distinguished 
  as 
  follows. 
  

  

  KEY 
  TO 
  GENERA 
  OF 
  SIALIDAE 
  

  

  Imagos 
  

  

  a 
  Fourth 
  segment 
  of 
  the 
  tarsus 
  bilobed 
  ; 
  posterior 
  branch 
  of 
  the 
  radial 
  sector 
  

  

  forked. 
  No 
  ocelli 
  Sialis 
  

  

  aa 
  Fourth 
  segment 
  of 
  the 
  tarsus 
  simple, 
  cylindric 
  ; 
  posterior 
  branch 
  of 
  the 
  

   radial 
  sector 
  simple. 
  Three 
  ocelli 
  

  

  